


Survival of the fittest

by FireBright



Series: Xenomorphic [3]
Category: Undertale (Video Game)
Genre: A little graphic but not much, Alternate Universes, F/M, GB- Is short for Gaster Blaster (Not Great Britain xD), Gen, I will add those if they are brought up!, Ink and Error tale, Other Universes may be mentioned, Timelines, Underfell
Language: English
Status: Completed
Published: 2016-08-29
Updated: 2016-09-11
Packaged: 2018-08-11 21:22:29
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 10
Words: 11,426
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7908076
Author URL: https://archiveofourown.org/users/FireBright/pseuds/FireBright
Summary: <blockquote class="userstuff">
              <p>-Underfell- Error teleports you to a dimension you wished you weren't in.<br/>-Undertale- Sans worries about your increasing absence, but something bad is happening while you're gone.</p>
            </blockquote>





	1. Stepping into the flames

**Notes for the Chapter:**

> Sorry for the delay guys, been a heptic week.  
> I was away the first day, then on the second day my dog got hit by a car, (Thankfully she's still alive!) The third day I had my hair bleached and was 99% close to passing out, twice. And today I went to meet some old friends who I haven't last seen since I was five or six. I was just so tired every day that I just wasn't physically and mentally able to write any decent chapters! So finally, here you go guys!

You were left there. Left in the icy landscape, hiding behind a large, charcoaled fir tree. You were scared and alone, but somehow you knew you had to survive. No matter what this world was going to throw at you, you were going to face it with the little sparks of Bravery in your soul. You were stronger than any monster, weren't you?  
"Howdy! I'm Flowey, Flowey the flower!" You looked at the flower in anger and fear, quickly morphing into your GB form to blast it's petals to dust. It watched in horror as you opened your jaws to charge the attack and cowered against the greyish snow.  
"Wait! Please I don't want to hurt you! Not like the other monsters!" You paused and stopped charging to look at him curiously. Was this a fucking joke? Mr. I'm going to murder you and take your soul, was acting nice? You rolled your eyes, of course it's a trick, he acted like this when you first met him.  
"And how can I trust you, ASRIEL?" You spat out his name and he gulped nervously.  
"How did you..." He slowly shuffled backwards.  
"That's right, I know who you are and I know exactly what you want to do to me. You want to kill me and take my soul so you can do something absolutely horrible to both humans and monsters!" He shook his head and shivered you raised an eye.  
"W-What, no! I would never harm a human. I'm sorry, you must have met one of the other monsters before you met me, did they hurt you?" You shifted carefully back into your human form mouth ajar.  
"Are you pulling my leg?! I know who you are! Stop acting so nice! I know you just want to backstab me!" He looked hurt at your words and stared at your feet trying not to make eye contact.  
"Please, trust me! I don't know what you're talking about. I just want to guide you to stop you from being brutally murdered down here! It's really not a nice place!" You pondered on his words and opened your mouth to reply with an unsure statement but the flower's eyes darted to yours in panic, stopping you.  
"Quick! Get out of here!" You furrowed an eyebrow in confusion after he buried himself deep within the snow but it didn't last long as a sharp bone pierced through your leg. You shrieked in agony as crimson blood stained the grey snow beneath where you stood. You fell forwards and tears of pain trickled down your pale face.  
A deep sounding voice echoed from behind you.  
"Well. What do we have here? Too precious for this world aren't 'cha? But don't you worry, pet. I'll take good care of you while boss is on guard." Another sharp bone was impaled in your wounded leg before you blacked out.  
\----------------

**Notes for the Chapter:**

> Yeah, short chapter. I didn't want to give too much away before the next one. I guess this is a good teaser/intro to the story, I think that this book will be longer than the last one but who knows? I'll just have to keep going and see if I still have ideas as I edge on in! This book should be very interesting knowing the behaviours of the monsters, but I don't know if I will be good enough to display their characteristics, it might be a bit weird...  
> Anyways please enjoy it! I love to hear feedback so don't feel scared to leave any critical construction comments in the comment section. Also, I aim to get 10,000+ words per chapter so that's why it takes a while to write each one. Thanks for the support- FireBright <3


	2. In another world

**Summary for the Chapter:**

> Back at your universe strange things are happening and it's not good...

**Notes for the Chapter:**

> I said I'de upload it earlier today... that was before my day went to shit... xD I tried!

-Sans-

_I remember tears streaming down your face when I said I'll never let you go..._

I didn't turn off the radio, I just listened and thought of you hoping that you'd come back soon.

_When all those shadows almost killed your light..._

When were you going to come back? It had been way longer than a week since you had gone.

_I remember you said don't leave me here alone._

I pushed off the sofa and placed my hand on the window sill, looking outside upon the surface. If only you were here with us. I just hoped that with all my heart you would just reappear one day.

_But all that's dead and gone and passed tonight._

I walked over to the radio, tears blurring my eyes, and switched it off. I stood motionless for a minute just staring at the radio in silence with my hand stiff on the top of the box-like object. I thought deeply of you, were you gone forever?

"What's wrong Sans? You haven't been yourself all week, I'm worried." My brother spoke softly from the kitchen doorway.

I sighed and took my hand slowly off the radio turning to sit down on the couch again, Papyrus followed sitting down next to me.

"I miss her so much." Papyrus put a hand on my shoulder to comfort me and pulled me close.

"Who is she?" I jolted my head upwards to face Papyrus in anger and confusion.

"What do you mean who?! ______!" Papyrus blinked and went still for a moment, then shook his head as if he was remembering something. I glanced curiously at his eyes which brightened slightly.

"Oh... Sorry... I forgot for some reason?" I was furious, how could he forget?! She was life changing! I gritted my teeth and stared at him.

 "I don't know why I forgot... it must have been all that work we have been doing lately." I shook my head and got up from the sofa. He looked at me hurt as I unlocked the front door to go out.

"I need to go outside for a bit." I spoke as I gently closed the door behind me.

I started to walk to the park or the woods, just somewhere to channel my shapeshifting powers so that I could release some energy. I shifted quickly and bounded into the woods, heading towards a stream that I found was serene and a nice place to escape both the other monsters and humans. It was only a ten minute walk away from where we had built our house or a one minute run in GB form. However when I got there I was tired from the running and jumping over obstacles to get there, so I sat at the waters edge and stared into the crystal water.

The water was beautiful in the light of the sun and reflected my skull, small fish were swimming through the stream trying to avoid my presence as they went. I dipped a paw into the cool water and the fish swam away or around it escaping my paw. I let out a sigh and drank from the side of the stream. If there was any bacteria in the water it would not harm me because of my wolf side but even if it could I didn't really care because it was so refreshing.

I stayed for a while and thought about heading home but decided that I would visit another instead. As I approached our home I turned towards the house next to it and rapped on the door.

"Who's there?" A voice sang from the other side, I paused for a second.

"Bones." I replied and she let out a happy sigh.

"Bones who?" She asked as she chuckled quietly.

"Sherlock Bones." She laughed and opened the door wide, welcoming me in, I smiled trying to hide my sorrow under my fake happiness and stepped inside.

"Hello Sans! It's good to see you again! I was getting anxious about your sudden isolation from all of the other monsters!" She smiled and I tried let out a half hearted laugh only to sigh.

"Sans! What happened?! Your not your usual punny self and there are dark patches under your eye sockets!" I slumped into a chair at her kitchen table and she offered me some tea that humans drink, I put my hand up and shook my head in answer and she sat down opposite me.

"Did something happen between you and Papyrus? Is everything okay?" I looked up at her in shock, how did she not get it? You had been gone for a week now!

"She's still gone, Tori. I don't know if she's coming back or not!" She leaned towards me.

"Oh Sans, excuse me asking but who is it that you miss?" Stars above! Is she freaking stupid?

"______! _____, Tori! Why would it be anyone else?" I regretted my words after I said them, she was probably really upset now for saying that in such a way. However she didn't display any hurt as her eyes brightened and she shook her head. Just like what Papyrus had done.

"Uh... Tori?" She sighed.

"Sorry Sans, I don't know what happened... I don't want to say I forgot about her but..." I was shell shocked. What was happening? Was everyone forgetting about you? How? Why?

"Uhhh... No worries Tori... Actually I should be getting back to my house, I did kind of stun Paps when I ran out for no reason!" I knew that wasn't the reason why I was really leaving and it was a stupid excuse but she still nodded and assisted me to the front door.

"Do come back soon, Sans! Remember your always welcome here!" She called out as I walked to my front door.

Once she had closed her door I glanced up at our house and teleported to my room, quickly locking the door and slumping down onto my bed.

'Gaster!' He grumbled and I realised I must have pulled him out of his work to try and find you again.

'What, Sans?' He complained and I shifted nervously on my bed.

'Is there a possibility that people could forget about _____ when she's gone?' He hummed.

'Yes an extremely high possibility, because she isn't in this Universe slowly everyone will lose their memories of her.' I gasped in fear.

'Does that mean I will eventually forget her?!' I almost shouted outside of my thoughts but stopped myself.

'Doubt it, Your connection with her is very strong, you think about her every second for Asgore's sake! Then again if she is gone for too long you will eventually forget about her unless the universe's energy forces you to forget.'

'What so I'll never remember anything that she has done?' I thought-shouted.

'Yes, until she re-enters the universe.' At least I would remember you when you returned.

'If you do forget about her, don't think I'll remind you. You would be better forgetting about her for now, it's changing you for the worse.' I just sighed and unlocked my bedroom door, I thought about apologising to Papyrus and yawned. That could wait till later, I came to the conclusion and decided to sleep it off for now. I returned to my bed and lay down staring at the ceiling.

Where were you? Were you okay? Were you hurt? You could even be dead by now. I turned onto my side trying to brush away my concerns and slept for the first time in four days.

**Notes for the Chapter:**

> Song mentioned-  
> Nightcore- Safe and sound.


	3. Chained like a dog

**Summary for the Chapter:**

> You wake up in a very unwelcoming home.

**Notes for the Chapter:**

> There's quite a few swears bearing in mind. But then again there will be more in the future because it's Underfell.

You struggled against the brightness of the room, your right leg hurting like hell. Blinking several times your eyesight slowly stabled still a bit blurry from waking up, you seemed to be in Sans's room but the air and colours of the room was different plus the treadmill seemed to be replaced with clothes that had been dumped on the floor. You tried to recollect your thoughts. How long had you been here? Suddenly voices seeming from downstairs caught your attention and you stood up painfully and quietly stepped towards the door.

"SANS! YOU HAVE ONE MORE DAY! THEN THE BITCH GOES!" It sounded like a deeper voiced papyrus. You covered your ears slightly with the sudden yell.

" _I know_ boss! She's fine!" Sounds like Sans. You heard someone growl, whether it was Sans or Papyrus you didn't know.

"YOU FUCKING SHOT HER THROUGH THE LEG! TWICE! SHE'S BEEN UNCONSIOUS FOR TWO WHOLE DAYS ALREADY AND IF SHE DOESN'T WAKE UP BY TOMORROW SHE'S GOING TO BE DEAD MEAT!" A door was slammed before loud footsteps were heard, coming up stairs.

He was coming. He was coming towards the room you were in. You panicked. If only you knew how to short-cut like Sans, you'd be out of here in seconds. Loud, angry mumbling was heard outside of the door as the handle started to turn. You felt pure adrenaline pumping through your muscles. Fight or flight. You stepped away from the door a couple of meters and shifted into your GB form. Flight.

The door was slowly pushed open and before the open mouthed Sans had any time to react you leaped at him, pushing him to the floor, and leaped from the second floor of the house to the ground floor taking impact from the land. You ignored the stairs.

"What the fuck?!" The skeleton shouted in shocked anger getting up from the floor.

But before he could come after you, you shoved your weight at the front door and ran out into the snow shocking all the villagers and Papyrus who was stomping away from the house. You sprinted into the forest ignoring the pain in your leg, hoping to get to the hill that you and your Sans visited, you hoped that he wouldn't come after you or find you but you knew he would. Still you ran, looking over your shoulder to see if he was still there, he wasn't. You sprinted as fast as you could all the way to and up the hill, wreaked with adrenaline and exhaustion from escaping the skeleton's grasp. Slowly, once sat at the top of the snow covered hill, you started to calm down, your non-existent muscles contracting and your breath steadying. You were safe. For now.

You sat on the top of the hill for a while looking to try and spot your kidnapper but you couldn't, relieved that he must have gone back in the house, you strolled towards a small cave behind the hill. You and your Sans had visited it a few times if it started to snow while you were on your midnight treks. Luckily there was no evidence of anyone ever visiting the cave so you presumed that this Sans hadn't seen it before. You settled down on the floor brushing the white vines that hid the opening back to their place and sprawled out on the floor head on your two front paws. It wasn't as comfortable as Sans's room but it felt a lot safer. You tried to stay awake to guard and see if he was coming but slowly you gave in to sleep.

\---------------------------------

 

"Hey pet. Gave me a shock when you ran out a while ago!" A voice sneered. You shot bolt upright and growled at the threat. He just stood arms folded, leaning up against the wall of the cave looking amused by your stir.

"How did you find me?!" You growled in a threatening baritone. He sucked in air through his teeth and gave a sarcastic hurt expression.

"So you have a voice! Shame it bites! Oh and you didn't cover your tracks. Survival rule number 1!" You growled at him and raised your back in an aggressive posture.

"Aw c'mon babe, don't give me that!" You charged a plasma beam.

"I'm not your babe. Not in this universe." He raised an eyelid showing his red, glowing eye.

"No? Well. In what universe are you my babe?" You gulped. you didn't want to tell him about your universe so you stayed quiet. He took the opportunity and raised a hand surrounding you in his red magic, you growled at him unable to move your limbs. Then without warning he dropped his arm and you slammed into the floor with a loud thud. You cried out in pain and he sneered.

"I'm going to give you a choice here. You can come back with me **o** **r I will kill you where you stand.** " He spoke with venom on his tongue leaving you paralyzed where you stood and staring in disbelief. He seemed to take the silence as an answer and came towards you. You stepped backwards as he approached cornering you. Your eyes darted towards any escape routes to which he rolled his eyes at.

"If you're thinking of escaping, think twice." He materialised bones to cover your only exit out of the cave and you stood in fear.

There was only one option left. Blast him. You charged a plasma beam and the cave lit up in a whitish-reddish colour he gave an annoyed glance and raised a hand, shutting your jaw with red magic and cancelling the charge. You growled in the back of your throat.

"Stop trying to kill yourself and work with me here!" He complained. You stopped growling and stared angrily at him he rolled his eyes and brought his other hand out from his pocket, holding a large, spiked, golden coloured dog collar. You started to growl again.

" **Don't you fucking dare put that on me."** You growled, surprised that your voice could get that low.

He took no notice and surrounded you in red magic again, lifting you off the ground, so you couldn't bite or attack him. Then slowly he unlatched the collar and placed it gently around your neck ignoring your protesting growls. Once he had re-latched the collar he stepped away to admire his handiwork and gently placed you back on the cave floor. As soon as he released you from the magic that encased you, you started to scratch at the collar to which he stared at you annoyed and shoved his hands in his hoodie pockets. A jolt of electricity came from the collar and travelled through your bones. You yelped and fell to the floor.

"What? did you think it was just a normal collar? Nope! I bought an extra-special shock collar for you so you wouldn't try anything stupid." The skeleton smiled darkly and unzipped his black hoodie to show a red t-shirt.

"Plus, it matches mine!" He showed off a collar that matched the one he had put on you, this one had a golden chain leading from it though, you were confused. Was this some sort of fashion thing around here?

"Why are you wearing a collar?" He looked away from you in shame and fidgeted with something in his pocket.

"Boss makes me wear one... Supposed to keep me 'Under control' and he uses it to wake me up if I fall asleep." He mumbled, you felt some what sympathetic for him but him noticing your expression quickly changed his sad looking expression and took a long golden chain out of his pocket. Before you could realise what he was doing he attached it to the collar you were wearing and grasped the end that wasn't attached tightly.

"Lets go, pet." He spoke before attempting to pull you out of the cave. You dug your heels into the ground reluctant to leave like that but after a warning jolt of electricity you hesitantly stepped out of the entrance.

 

So this is what being a dog felt like... You weren't very determined now...

**Notes for the Chapter:**

> Thanks for reading! And no, this is definitely not the start of some stupid tied up porn thing, which is just weird and cringy... Anyway, thank you for reading and extra thanks for the kudos and comments! Also chapters daily etc etc etc... I'm tooo tired right now and my brain just died, I just tried to use one of these- ! as one of these- ' ... It's way too late for this and I need to just curl up in my bed and die! xD Cya later guys!


	4. Taken away from freedom

**Summary for the Chapter:**

> Sans takes you back to the house

**Notes for the Chapter:**

> I can no longer tell if I'm reaching 10,000 characters or not xD the countdown thing isn't working! Still! It doesn't really matter too much, I usually write that much anyway!

The skeleton lead you back to his house quickly checking over his shoulder every minute to see you head scraping against the snow with every stride. When you came to the edge of the forest Sans quickly checked to see if there was anyone walking in the streets, to your surprise there was only a monster walking in the far distance. It must be night on the surface. So with seeing a deserted street Sans lead you towards the door of the house and pushed it open quickly.

He stepped in and tugged on your chain to get you to come in. You stood dazed on the doorstep and looked inside the house nervously. It couldn't be that bad, could it? Your magic would work soon and you would teleport away to some friendlier universe, wouldn't you? You just had to wait and find out.

"C'mon pet." The stout skeleton tugged again gritting his teeth. "Come. on." You brought your attention back to the skeleton and stepped slowly and carefully into the house.

He shut and locked the door behind you as you turned your head to find the exit. You drooped your head. No escape now. A heavy metal looking Papyrus stepped out of the kitchen and walked over to your face lifting your head with his hand.

"YOU CAUGHT THE BITCH THEN." He spoke simply in a harsh tone. "

" **I'm not a bitch.** " You replied venom on your tongue, not metaphorically anyway. He shrugged and walked back into the kitchen.

"MAYBE YOU'LL DO MORE WORK THAN SANS. WELCOME TO YOUR NEW HOME, WOLF LADY THING." He called out of view of you and Sans.

Sans took off the chain on your collar and hung it next to the door. You felt slightly more free even though he still made you wear the collar. Sans gave a curious glance at you before walking over to the sofa and taking a seat as if it was a perfectly normal day.

"Might as well make yourself at home, you aren't gonna be leaving Snowdin's boundaries." He spoke from the green torn sofa barely looking at you as he talked. You sighed in defeat and turned back into human form to save your magic only to be able to barely breathe because of the collar, your GB neck was smaller than your human neck for some reason. You fell to your knees and clawed desperately at the collar, Sans peered over the side to zap you with electricity.

"Stop! Can't... breathe." He turned his expression into a shocked one and jumped off the sofa running over to you. He grabbed the collar around your neck and loosened it quickly. You panted rubbing where the collar had been.

"Th...Thanks." He looked surprised for a moment before heading back to the sofa without another word. Papyrus interested in the sudden event stood in the kitchen doorframe a plate of spaghetti in one hand. After seeing no action he shrugged and walked back into the kitchen.

"Do you swear a lot?" Sans asked you from the couch peering over the side to face you, what a random question.

"A bit? I guess." He hummed.

"Well we do it a lot here so you might as well join in. Oh and by the way Papyrus is cooking his 'extra special' spaghetti. Again." He chuckled adding exaggeration on the 'extra special' bit a low growl was heard from the kitchen.

"SANS YOU MOTHER FUCKER, STOP TALKING SHIT ABOUT MY MASTERCHEF CULINARY SKILLS!" Sans laughed at his brother's complaint.

"See." He told you before grabbing the tv remote and switching it on.

"Sorry the only show that plays in the underground is-"

"Mettaton's. Yeah I know." You spoke surprising him as you took a seat on the sofa, next to him.

"How did you know that? What are you some sort of mind reader?!" You thought for a moment of what to say.

"Yeah, I'm a mind reader and I can breathe fire." You wiggled your fingers for exaggeration and he smirked.

"Doubt that humans can breathe fire, the only person I know who can use fire is-"

"Grillby, yep." You cut him off quickly he stared at you in awe.

"You are a mind reader aren't you?!" You shook your head.

"Nah, I just know about them in a different world." He looked puzzled for a minute before diverting his attention towards the tv.

"So what makes this place so bad anyway? I mean apart from the fact you kidnapped me and you're using a shock collar on me." He looked at you in stunned silence.

"Are you fucking blind!? How many monsters have tried to kill you since you were down here?! How many?!" You tilted your head to one side.

"Uhh... none? I mean apart from you."  He got a bit frustrated with your words.

"I didn't try to kill- Wait what? None!?" You nodded.

"How long have you been down here?!" You thought for a while.

"Since you assaulted me, plus about a couple of minutes before that." He mouthed several swears before turning to you again.

"What?! Did you just appear out of thin air?!" You swayed your head from side to side looking at him in a thoughtful manner.

"Yeah... I guess if you put it that way." He opened his mouth in shock.

"SANS, HUMAN. SPAGHETTI, TABLE, NOW!" You both stood up and headed to the kitchen, Sans's mouth still wide. Once you had sat down he started firing questions at you again.

Papyrus sat at the head of the table equally interested in your answers but he tried not to show his interest by sticking a fork into his spaghetti and eating it quickly.

"How did you get in the underground then?" Sans asked ignoring his plate and seeing an excuse to not eat it. You saw an awful joke rising in your head.

"I went to France." He swore under his breath before pulling his plate of pasta closer to him.

"What do you mean you went to France? How does that have anything to-"

"Eifel." He stopped and looked at you humour in his eyes before bursting into laughter.

"JESUS FUCKING CHRIST!" Papyrus yelled slamming a fist to the table just making you laugh like hell.

"I could get used to this!" You spoke to Sans, secretly pointing to Papyrus as he almost flipped the table in rage.

Sans snickered his laughter calming and returning to his normal expression but this time his mouth stretched in a smile.

"In all seriousness now, _how did you_ get down here without any monsters beating the crap out of you?" He waited for an answer patiently.

"WHAT? APART FROM YOU TEARING THROUGH HER LEG WITH TWO BONES?"  Papyrus spoke mockingly Sans growled.

"I mean... I was actually attempting to commit suicide the first time I fell." Sans raised an eyelid.

"The first time?" You nodded.

"Yeah, not in this universe though." Sans mouthed 'what the fuck' slowly before shoving a fork of spaghetti in his mouth.

"EXPAND ON THIS." Papyrus spoke to you. You nodded.

"I've visited two universes so far hoping to get back to my one. In my universe... Well the universe I think I belong to, I was underground for a month then I freed all the monsters also Sans in that universe was my 'boyfriend'." Sans choked on his spaghetti and Papyrus laughed at his brother's reaction.

"Lets... lets move away from that subject." Sans spoke after containing his choking.

"Anyway, when I got to the surface me and him watched the sun set and we started to walk down the side of mt. Ebott to catch up with the others when, to put it simply, I teleported beyond my control to another universe." The brothers looked at you in curious silence.

"Then the cycle started again falling into the underground meeting all the monsters, which were now different with swapped personalities, freeing the monsters. That time I waited and waited for my magic to teleport me, hopefully home again, but it didn't work. So that Sans took me to his friend which was supposed to take me home but instead he dumped my in this universe because apparently that Sans was his friend and his friend only." Sans snickered and Papyrus sat looking confused.

"So, In other words you have this out of control magic problem which teleports you to other universes, also because of some friend of mine in another universe he got jealous and dumped you here." You nodded.

"That's why I 'appeared out of thin air'." He shrugged slightly humoured by your problem and started eating again.

You took your first bite of the spaghetti Papyrus had made and was surprised by how good it tasted unlike the Spaghetti in your universe.

"Holy shit." You spoke alerting Papyrus at the head of the table. He looked at you taking it as offence.

"WHAT IS MY SPAGHETTI NOT GOOD ENOUGH FOR YOU?!" He shouted.

"No! No! No! It tastes amazing! It's great Papyrus!" You ate another forkful to prove his point.

"THANKS... I GUESS. UNDYNE AND GASTER TEACH ME." He replied.

"Gaster? Oh crap Gaster!" You remembered Gaster who was most likely dead with worry about your vanishing into another universe. The two brothers looked up at you in interested alarm.

"Uhhhhh... Guys? Do you have any room which I can go in? I need to have a private conversation with someone." Sans looked up in interest.

"You can go in mine?" He told you before you stood up from the table.

"Thanks!" You called making the stout skeleton shake his head in a confused way as you took the stairs two at a time.

 

Poor Gaster and Sans they were probably more worried than ever before!

**Notes for the Chapter:**

> Thanks for the kudos, comments and hits guys! 100 hits already! Yeah! :D


	5. Catch up

**Summary for the Chapter:**

> You run to Sans's room to talk to Gaster...

**Notes for the Chapter:**

> Again, sorry I didn't upload this yesterday! I decided out of my own stupidity: Lets party hard and try to stay awake three days!... It took a toll for the worse... By the time I was nearing the end of the second day I felt really sick, I didn't want to eat anything and I felt like I had a permanent migraine... So I packed up for the day and just slept. So! That's why unfortunately you did not get another chapter... Sorry! I'm trying to do two chapters to make up for it but I don't know if I'll handle it, BUT I'LL TRY!!! Thanks for the support guys! -FireBright <3

You sprinted down the corridor to Sans's room, Sans watching you from downstairs as you ran. When you had tore the door open and closed it once again you started to calm sliding down into a sitting position with your back against it's wood.  
'Gaster? Are you there?' You asked in your thoughts. No reply.  
'Gaster?!' You waited nervously. No reply.  
'Gaster? Please!' ... No reply...  
Then suddenly the room faded to grey, you stood up anxious waiting for something to happen. Was he okay? Was he angry? Was Sans okay?! A sudden depression hit your heart. Sans...  
Gaster appeared in his first form and didn't say a word, a relieved looking expression hung on his face.  
"So Pet, Who is this frien- What the fuck?!" Sans appeared in the room presumably he teleported. You turned to face him and saw him as shocked as he was scared, he was staring straight at Gaster.  
"I-I can explain! Please!" You stuttered hoping that he wouldn't freak out. He backed up against the wall and stared as pale faced as a skeleton could get at Gaster, his orbs of light in his eyes shrinking to pinpricks. Gaster was also shocked at seeing Sans quickly trying to morph into his 'normal' form.  
"T-That's your friend?! T-That creature?!" You nodded hesitantly and Gaster morphed into his less terrifying form. Sans shook his head in scared confusion.  
"My name's Gaster but you probably know that already..." Gaster spoke approaching the stout skeleton like he was a cornered animal. Sans shrunk to the ground in fear as he approached and put his hands up to cover his head.  
"P-please... Don't h-hurt me!" He whispered shaking like a leaf. Gaster stopped in his tracks and knelt to his level. You stared at the two unsure what to do or say. Sans started to weep curling into a tight ball trying to protect his body. Gaster looked surprised at his reaction and sat by his side carefully. Sans immediately jumped up and ran to the other side of the room.  
"Sans please, trust me!" Gaster begged. You approached Sans's side in attempts to comfort him.  
"How?! H-How can I trust you after what you did to me?! I told you not to c-come back!" Sans accused Gaster pointing at him with a trembling hand. Gaster looked slightly hurt but tried not to show it.  
"F-Fourteen years! Fourteen y-years of hell Gaster! W-Why do you do this to me?! Don't act like you don't know!" He growled his voice and body quivering, you stepped back and looked glassy-eyed at Gaster. What was he talking about? Gaster looked back at you wearing the same   
"Sans... We don't know what you're talking about..." Sans shuddered and his eyes flickered.   
"Sans?" You spluttered. He didn't answer, staring straight through Gaster. Gaster stepped out of the direction he was staring in, he didn't faze, he just kept staring at the wall and shuddered again.   
"Sans!" You waved a hand in front of his face desperate to see him do something else. He swayed forwards and you put out your hands to stop him from falling, luckily you did stop him. But within a mere few seconds it didn't make a difference as his body went limp and he fell sideways to the floor.  
"Sans!" You called and kneeled at his side. Gaster also came over quickly kneeling to assist him.  
"What do we do?!" You cried out to Gaster. He didn't answer immediately, taking Sans in his arms and carrying him to his bed.  
"There's nothing we can do. We need to wait for him to wake again." Gaster examined his unconscious body checking for any injuries from the fall and sighed when he came across a large crack in the back of his skull. You looked at Sans panicking.  
"A crack. Old, but still, it looks painful." Green magic enveloped Gaster's hand as he gingerly touched Sans's skull after a few moments the crack glowed green but not mending. Gaster sighed and stepped back from Sans.  
"It won't heal, strangely. However I have temporarily eased the pain for him. Poor soul... I can't find any injuries from the fall he just took but there is a great deal of old cracks and chips in his bones. What happened?" You shrugged relaxing about hearing there was no new injuries. You should hate this Sans surely? He kidnapped you, stabbed you and now he's put you in a shock collar and calling you 'pet'. Why were you so protective towards him?  
"Well..." Gaster announced and put his hands on his hips to meet your glance. "I should be talking... Shouldn't I!" You cocked your head unsure what he was talking about and took a seat on the floor next to Sans's bed, he copied you.  
"When... When you teleported thanks to that traitorous skeleton, Error, I managed to follow you. As soon as you stepped through I tried to talk to you telepathically but the communications were cut off for some reason. Then that flower appeared." You looked at him curiously as he spoke explaining his problem.  
"Do you know why?" He looked at you and sighed slightly shuddering.  
"Yes... And that's why we... We have a problem." He stammered. You furrowed your eyebrows in concern and he took that as a cue to continue.  
"The Gaster in this universe... He's still alive... And he's not the type to mess with." You lightly laughed. You've dealt with so called 'hell' in this universe and it's not that bad! How bad can it be?! Reading your thoughts Gaster replied.  
"It's a lot worse than you think. I believe I know why Sans here fainted." You sunk into the carpet. It's not like it was something you can't handle... right?  
"Gaster here, is a scientist at the lab in Hotlands, he barely leaves the place. He is evil towards other monsters but maybe he will be different towards you?" Gaster spoke hopeful but still a little doubt hung in the air.  
"What do you mean by 'Will'?" Gaster sighed.  
"Gaster! Tell me!" He shakily looked at you and you stared at him slightly terrified.  
"You will meet him and you can't stop it. He can sense your presence in this universe but he cannot locate it. You have two attempts at escape. You can try to control your powers to teleport but there's a 50% chance you will teleport to a universe that's worse, die or at worst teleport to the void. Or you can keep running and hope he doesn't catch you." You looked shocked at Gaster unsure what to say. He just kept looking at you sadly.  
"Have you told our Sans?" He stopped looking at you and turned his attention to the carpet in shame.  
"N-no. He's worrying himself sick about you, if I tell him he will resort to doing something in panic or break down in depression. I don't have the guts to tell him the truth." You sighed and thought about Sans.  
"It's okay... I understand." You both stared at the carpet for a while in silence listening to the calm breaths that Sans took.   
"SANS?!" You heard Papyrus yell from downstairs and panicked. Gaster immediately got up from the floor.  
"I need to go before he sees me, I'll try to talk to you soon!" He blurted quickly before vanishing without another word. You were left to fend for yourself and Sans who was still unconscious on the bed.  
"SANS?!" Papyrus called again and you jumped up from the carpet.  
"OKAY SANS! I'M COMING IN YOU LAZYBONES!" Heavy footsteps were heard on the stairs as he approached your stomach was doing a somersault each step he took till finally the door was tore open revealing you standing in the middle of the room while Sans lay unconscious on the bed. Papyrus took a few seconds to focus on what was happening, standing in the doorway in shock.  
"HUMAN? WHAT DID YOU DO TO SANS?!" He boldly questioned. You stood paralyzed in fear.  
"I-It's not what is looks like!" You managed to say, Papyrus looked unconvinced.  
"FINE! IF YOU WON'T TALK, THE TRUSTY SHOCK COLLAR WILL WAKE HIM UP!" Papyrus reached into his black trouser pockets and pulled out a small remote.  
"No! Stop! Don't hurt him! It's not his fault!" You begged and Papyrus raised an eyelid.  
"DON'T ARGUE WITH ME HUMAN." He spat you took a few steps over to Sans and stood at his side where he lay.  
"Don't. Hurt. Him." You spoke through gritted teeth. He crossed his arms in challenge.  
"OR WHAT?" You shifted into your Gaster Blaster form and stood in an attack posture.  
"I will rip off your arms and shove them so far up your ass you will shit fingers for the next month." He uncrossed his arms and stared at you slightly shocked before stepping out of the room and walking out of sight. You sighed and morphed back into your true form knowing the threat was gone you sat at the end of Sans's bed and watched him breathe. You wondered when he would wake up. You waited a while before getting back up and walking out of the room, closing the door behind you. Once you were sure it was shut properly you walked down the hallway and then down the stairs, settling down on the couch to think. You thought about Sans and Gaster, then about this world's Gaster. Surely you could find a way to get past him? A loud 'NYEH' was heard from the kitchen and before you could react a bone was impaled in your thigh. You screamed in pain and Papyrus laughed.  
"NO ONE THREATENS THE GREAT PAPYRUS!" He yelled and for the second time since you had been in this universe, you passed out.


	6. The masked villian

**Summary for the Chapter:**

> You awake in somewhere you had never been before...

**Notes for the Chapter:**

> It's late and its short! What the hell am I playing at? I swear, my writing will get longer!

You woke up after blacking out, again. You had gotten pretty used to doing it now and just sighed settling down into what you had been left to sleep on. You furrowed an eyebrow, your eyes still closed. Where were you? The scent was different clean smelling and you felt what seemed to be thick covers across your body. You hoped that you were in Papyrus's room rather than anywhere else.  
In the distance you heard voices, not close to the room you were in however. They were unique from the ones you had heard before but somehow similar sounding like someone who you knew. You slowly opened your eye just to close it again because what you were looking at was a flashlight. You winced and tightly closed your eyes hoping to block out any light.  
"I know you're awake. Open your eyes human." Spoke a familiar voice you kept them close ignoring his statement.  
"Open your eyes." You sighed and hesitantly did so relieved that the flashlight was no longer blinding you, green-black spots were left in your vision where he had lit up your eye. You took in your surroundings quickly noticing you were in a room with one small, high window, white walls and a cream carpet, you were laying on a bed which was plain which had a nightstand and a chair next to it. Upon the chair sat a tall skeletal man wearing a lab coat, Gaster. You panicked looking for escape routes to realise the only one available was being blocked by a manic looking Alphys. You panted and looked around in fear trying to find any tools or equiptment that Gaster might have brought in with him, but the only thing you saw was the flashlight that Gaster was holding while he watched you.  
"Where am I?!" You hurriedly asked. The scientist looked emotionlessly at you and raised an eyelid.  
"If you must know you are in the Hotlands laboratory, floor 7, room 12." You stared at him in fear and he put a hand on your back as you sat up to comfort you. You were shocked at his gesture and looked at him cautiously as if he could change any moment.  
"I will not harm you human..." He reassured you. It didn't work.   
"That's not what everyone else has been saying!" He flinched at your words and you bit your tongue. You regretted speaking, waiting for his call on Alphys to do something to you.  
"It seems to me we have got off on the wrong foot! I am Wing Dings Gaster but you can call me Gaster for short. What is your name?" He asked with a smile. You opened your mouth in uncertainty and he gave a patient smile.  
"My name... My name is _____..." You told him and he smiled broader.  
"Thank you. Now, is there anything you would like or need? Perhaps you have a certain medication you must take?" You shook your head and thought for a second.  
"A-Actually there is one thing?" He tilted his head to a side in interest. "F...Freedom? Can I visit Sans and Papyrus every now and then?" He narrowed his eyes for a second in deep thought thinking about whether he should or not.  
"Hmmmm... O...kay." He answered and your face lit up in a smile. "Even though I do not like those two, you have my permission." You thanked him and realised that something was missing. You rubbed your neck, feeling where the golden shock collar had once been. He nodded at you when you looked at him in surprise.  
"You took the shock collar off! Thank you!" He shook his head in disgust.  
"That was a shock collar?! I thought it was just a normal one! Those imbecilic brothers!" You felt sorry for the two for a minute and thought about them, but then you realised something.  
"How did I get here?" You asked curiously surely it wasn't the skeletons who took you?  
"Papyrus took you here, Sans was also tagging along, they dropped you off as soon as you passed out." He spoke you nodded in sadness at hearing they betrayed you and then realised he was lying, Sans was unconscious when you passed out!  
"Can I visit them today?" You asked and he shook his head.  
"No, you need to wait a few days for your leg to properly heal after you were attacked. Then I will consider letting you visit them." He raised from the chair and started to walk out of the room Alphys was already gone. If you need anything the room code is 3672 and my office is the last door at the end of the hallway." He walked out and closed the door behind him and the lock clicked shut. 

He acted like a nice guy, but under that smile you knew lurked a dark core. He might think he has gained your trust but he hadn't not a chance in hell.  
You were filled with DETERMINATION to escape!


	7. How to not train your human

**Summary for the Chapter:**

> Gaster decides to take you for training! Good idea? Perhaps not?

Gaster had told you to sleep, when he left after he visited a second time, he said you should sleep and it was midnight on the surface. You agreed and he walked out locking the door behind him. That was three hours ago.  
You wanted to sleep, out of all honesty. You were exhausted and magically exhausted. However no matter how much you writhed and turned under the covers you couldn't sleep.  
Eventually you gave up and looked around the room, you looked for any hidden cameras that invade your privacy but to your slight disappointment of no distractions to perhaps make you sleep, you didn't find any. You turned onto your side and sighed uncomfortably. You relaxed into the bed and grabbed a watch that gaster had left for you. 3:46 it read and you rolled your eyes placing the watch back on the nightstand. A small lamp lit your room and you hesitantly turned it off hoping you could try to sleep again, however after another hour of tossing and turning you realised that sleeping wasn't going to be an option.  
'G-Gaster?' You called in your mind. The room turned black and he morphed into reality.  
"It's almost five in the morning, _____... C'mon this better be good..." He grumbled softly and you were slightly shocked on hearing that he actually slept. He sat down on the bed, beside you and looked at you in concern.  
"I... I can't sleep..." You replied and he raised an eyelid shuffling to your side as you sat up.  
"Well, have you tried everything you can?" You nodded yawning which made him yawn.  
"I ahhh... I don't really know how I can help you dear _____, I'm a scientist not a psychologist." You grinned at his corny joke. He ran his fingers through your hair.  
"Is there something bothering you? Maybe that's why you can't sleep?" You shuddered slightly.  
"How's our world. Is everyone okay?" He awkwardly turned away and put his arms back to his sides.  
"Th-There's been an issue..." You tilted your head to one side in concern and he gulped.   
"Everyone, well, you see... Everyone is slowly forgetting about your existence?" You opened you mouth wide to yell 'what' but stopped yourself quickly.  
He nodded and got up from the bed.  
"It's no big deal! They'll remember you when you return! Maybe..." You flinched at his words.   
"What do you mean by maybe?!" He started to teleport away.  
"You know what. I need to go! Have a good sleep, _____!" Before you could protest he was gone. That just made things worse! You were now really worried and couldn't sleep at all! You led on the bed for a while which then turned into a minute.... then an hour and before you could do anything you heard the soft click on your door meaning that Gaster was coming in. You flinched and sat upright facing the door as he casually walked in.  
"Did I wake you?" He spoke before sitting on the chair next to your bed. You shook your head.  
"How did you sleep? Oh and how's your leg?" He asked and you scanned your brain for a lie.  
"Great thanks Gaster! And my leg doesn't hurt much at all! I'm barely hurting!" You replied a heavy tiredness hanging on your voice, the second part wasn't a lie, he didn't seem to notice and wrote a few notes on his clipboard nodding.  
"I wanted to take you to our training gym today so I can see your magic? And then once we're done we can have a friendly battle?" He questioned and you hesitantly nodded. You did feel like you could burn off some steam.  
"Good! Follow me!" He spoke before heading out of the doorway. You got up on your feet and started to follow feeling really dizzy from the lack of sleep, you did almost fall onto your face but Gaster caught you and swiftly you returned to your feet.  
You didn't travel for a long time, it was only a corridor away from your room.  
"Okay! Here we are!" Gaster spoke as he pushed the gym door open. You followed him inside.  
It was a large room with a bench next to the door. You saw that there was several char marks and dents in the wall where others had practiced.  
"So, lets start off with your so called 'Shape-shifting'." Gaster spoke and you transformed quickly, obeying him.  
"My word! You do have some sort of extraordinary talent!" He spoke and wrote notes on his clipboard.  
You sighed and turned back into human form as he frantically wrote.  
"What else can you do?" He questioned and you summoned a scythe in your hand.  
"Pretty much what Sans can do." You shrugged and he nodded understanding.  
"Well! That's the first lot of questions answered, now the next is to do with combat. Do you think you can handle it?" He questioned facing you in thought. You nodded raising up to the challenge.  
"Good! I want you to attack this target in your other form, please!" He announced pointing at a target hanging on the wall. You charged your plasma and fired at it, hitting the bullseye.  
"Wow! You can control your magic well!" He complimented before scribbling down notes again.  
"We shouldn't need to worry about that! Now your defence?" He spoke before summoning a few bones. "You can choose to dodge or block them, whichever you prefer!" You nodded and he threw the bones at you.   
A flashback hit your mind: you were practicing with Sans to control your magic and then he launched bones at you, you dodged the first few with ease but the last one scraped your shoulder.  
"Watch out!" Gaster called bringing you back to your thoughts but then it was too late and the third bone cut through your shirt and ripped through your skin creating a deep wound on your left arm. Gaster ran over dropping his notes on the bench.  
"S-Sorry... I-I got a vision of something..." He looked quizzical and reached into his lab coat pulling out a first aid kit.  
"It's a good thing I brought this!" He opened it quickly and grabbed the bandages, wrapping up your bloody arm. Red stained the fabric and there was blood on your shirt at least you didn't bring Sans's hoodie with you! Gaster was considerably good at wrapping up your wound, soon he pulled away and tucked the First aid kit back into his coat.  
"Lets take you back to your room, We can train again another time." He spoke before leading you back to your room and locking you in. Once again you sat on the bed and tried to get to sleep.

"Yeah... Another time..."


	8. Discord in the air

**Summary for the Chapter:**

> You decide to visit the skeletons.

**Notes for the Chapter:**

> Hooooly shit... I am so sorry! Like 4 chapters behind?! I honestly don't mean to guys, it's just been really crazy lately and I haven't had the time nor the energy to write chapters! I apoligise once again, and I'm going to try and catch up again!

You had been in this 'dreaded' world for about three whole weeks, not having enough privacy to connect to your world, when Fell-Gaster (Or so you now called him, to make things easier) came into your room, that game changing morning. You had been pretty confident that your magic would work soon teleporting you to a place either worst of better than this one, however to no avail. Gaster seemed like he was growing to like you ,in fact, as you improved on your training, but whether this was a liking towards you or your abilities was hard to breach. You suspected it was more likely the latter one as Gaster's notes soon started to frantically expand. You did manage to look at the notes he had written once, however it was either written in a strange language or he just had awful hand writing.  
You brought your thoughts away from the symbol looking handwriting and back to reality soon to quickly return to your aimless thoughts. At any moment Fell-Gaster would walk in with breakfast for you, then the daily plan was to do training. Except today it was a Saturday on the surface and he let you have spare time days on Saturdays, letting you explore the lab or crash with a book in your bed. You had something special to ask him today, your leg had fully healed, thanks to the medicine and monster food Gaster was giving you, and you hoped that today you could go further than the lava surrounded lab and back to the cool, dusty snow. Even if the trees were charcoaled and clouds of dust thickened the air, it was home like, as you had spent a month or so with your skeletal friends there. On the contrary you missed the small village and the tall hill overlooking the town, that you and Sans had visited time to time. You gritted your teeth slightly. There was one thing you wanted to clarify however. You wanted to know why Papyrus had dumped you to a lab filled with; dangerous machines, hazardous chemicals, strange looking medicines and an insane looking Alphys. Now that you think about it you hadn't seen Alphys for the last week. What was she doing?  
As you started to imagine what experiments she was working on, you heard your door click shut as a hand landed softly on your shoulder. You jumped a bit in surprise making Gaster smile. He slowly and carefully your meal over to the nightstand, placing it down smoothly before returning to your side to take a seat next to you on the bed. You looked up at him noticing how considerably taller he was even though you were 5'8" he looked as if he was about 7'0", Perhaps it was because he was a monster skeleton and not a human one?  
"So _____, I believe you would like to not train today and do something else?" He spoke softly. You nodded in reply and he nodded back smiling.  
"I see, what would you like to do?" He questioned asking in a careful tone to keep you comfortable. You thought about wording your reply for a moment, cautiously choosing the words that seemed right.  
"If it's okay, Gaster, may I visit Snowdin? I'm feeling a bit homesick knowing that I did spend at least a month there with all my friends." You asked quietly but confident. He turned his head forwards and went still, for what seemed forever, debating in his head whether you should stay or go, you even started to sweat at the thought of him disagreeing. Eventually he nodded slowly and you wiped the sweat of your brow.  
"I guess you can go... Your leg has healed properly and if you won't ru-Injure yourself while your visiting I don't think it would be fair to not let you go!" He smiled nervously at you but it didn't stop you from feeling uneasy for a moment, thinking about what he had said to you, did he almost just say 'run away'? You felt uncomfortable around him now but shook it off quickly to stop him from noticing your change, you nodded excitedly, happy to get to visit your 'friends' again, but more importantly get some answers from them. This was going to be a looong day.  
It was a calming feeling that took you, as you thanked the river person while stepping off the long, wooden boat. The icy winds bit at your face yet it wasn't uncomfortable, snow covered your shoes and melted into polar temperatures, soaking into your socks. You walked swiftly to the front door of Sans and Papyrus's house and lifted your fist to knock, but before your fist could make contact with it's hard surface it was thrown open to reveal a almost teary-eyed Sans. You didn't comment, shocked at his appearance but in the end it didn't matter because before you could announce anything you were grabbed by the hand and pulled inside to your surprise.  
He closed the door behind you quickly and bolted it shut as if it were the apocalypse. Only until he had made sure that the door was properly locked did he face you, slightly calmer than what he had been before.  
"Sans?" You asked, expecting him to take it as a sign of worry. He sighed and pulled you over to the couch, taking a seat himself next to you. Although he put a face of complete calm on, you could tell that inside he was panicking.  
"What's wrong Sans? He ignored your comment and started to ask you questions.  
"Where is he?!" He asked, his fake expression slipping quickly. You tilted your head to a side in confusion, who was he talking about?  
"How did you escape? Did he hurt you? Are you okay? Is he at the lab or did he follow you? I swear if he has hurt you it will be the last straw!" He blurted out quickly, you struggled to keep up with his questions and didn't answer till he calmed down.  
"You're talking about Gaster, aren't you?" He shuddered at the name and nodded. You figured that you would cut to the chase and ask them how you had even ended up in the lab to begin with.  
"I'm fine. More importantly however, what the fuck were you doing by handing me into the scientist that wants to use me as a lab rat?!" If you could hear hearts sinking then right now Sans's would be the loudest ever.  
"Don't trust him, whatever you do. He acts nice but it's just to gain your trust and make your soul burn brighter before he decides to experiment on it." You gritted your teeth in anger for him not answering your question but also felt worried at his description of the science skeleton.  
"Thanks for the tip but don't change the subject please." He let out a raspy sigh before giving in and answering you in concern.  
Don't you get it?! We didn't take you to his special hell..." You stared at him slightly anxious opening your mouth in shock.

"He came to us."


	9. Uncovering the truth

**Summary for the Chapter:**

> Sans tells you his backstory as you offer to stay the night.

**Notes for the Chapter:**

> I... I have no notes I can say xD  
> well apart from... PARTY LIKE IT'S THE ROARING TWENTIES! For some reason?! xD

You stared at Sans mouth agape. Lies. How did Gaster know that you were here?  
"You don't believe me do you?" You hesitantly shook your head. How could he find you in so little time?  
He sighed and looked around the room, funny, Papyrus was apparently not home.  
"Well... Even if you still think that we took you to him... We... We missed you a lot. We were so worried and you know that after that 'episode' a couple of weeks ago I can't even approach him without feeling paranoid." You nodded. That was definitely true, Sans would never take you him.  
"As you know I was unavailable to take you to Gaster," He shuddered at the name but quickly moved on. "Papyrus... He was a bit young but he would still remember what he did to me... What I'm trying to get across here is that even in this world where it's kill or be killed we have two members of the underground that we all fear, Asgore and... him. We would never and I mean never hand over someone that is useful to us, to either of them." You were quite content with his words but one word just stood out among them.  
"Useful?! Is that all I am to you?!" He stood up and shook his head in shock you stood to join him.  
"Look here Sans. I might just be another human to you but in reality you are all my friends, even if it is in another universe!" He looked down in shame and apologised quietly, you felt sorry for him, he probably hadn't had a friend ever thanks to his backstory and universe. You stepped forward and hugged him, smiling.  
"It's okay, I'm okay now." He was shocked at the embrace his body stiff and fingers outstretched but soon he calmed down and brought his arms around your back. He put his head down of the fur of Sans's hoodie and softly cried into your shoulder. You rubbed his back comforting him.  
Eventually he pulled away and looked at you thankful for your action. You smiled reassuringly.  
"It's okay. I'll come back I promise. I just don't know if I'll have gone by then because of my magic though." He nodded his expression unreadable.  
"We are going to get you out of there. We won't let him do his experiments on you. If he does you will end up like me. Once I had a pure soul, Much like yours, but it doesn't matter how much you fight or how tough you are he can still break you in." You nodded trying to look brave but gulped at his words. You would make it through you just needed more preparation, surely?  
You felt uncomfortable about the increasing darkness on the subject and decided to change it.  
"So... Has there been any other humans to fall?" He gulped and looked away from you slumping back on the surface. You two sat down and face him, tilting your head in interest.  
"Th-There has been... some..." You suddenly felt unsure about the subject but carried on listening. You found a corner of the blanket thrown across the sofa and fiddled with it nervously.  
"As you're not familiar with our story I'll tell it to you... Monsters and humans once lived in harmony on the surface but then one day the monsters realised that the humans had power over the monsters. The humans were scared of the monsters and frowned apon them, wishing them to die out... The monsters got sick of the humans, but the thing that triggered the monsters to retaliate was the death of the prince. He was murdered by a gang of the humans lead by the prince's once best friend. We don't speak their name... The monsters were in rage and sent out assassins to slowly wipe out the group. They were successful apart from the leader who escaped never to be seen again. The monsters felt powerful again after destroying the group. They started to assassinate more humans, ones that had done wrong towards monsterkind or wouldn't serve them in shops. The monsters were taking any chance they could to murder the humans, the main cause being the feeling of their LOVE increasing. It felt like a drug to them, once you had killed one you wanted to kill another, then another, then another, etcetera. This spiralled out of control soon the humans declared war apon the monsters, the humans had technology but the monsters' LOVE was more effective. The monsters wiped out human kind there were few survivors but those survivors came together and locked the monsters underground, they sacrificed their souls to create a barrier. We don't know how many humans were remaining when we were trapped underground but if any do fall, the monsters kill them immediately. Unfortunately the ones who have fallen... Were only children." You opened your mouth in shock at his words. How many innocent children were murdered?! He nodded at your shocked look.  
"I didn't want to kill any of them really. It was the others who did. The war wasn't long ago. I was in training and my so called father was 'training' me. He gave me determination from the human souls declaring that I would be the strongest soldier. It was against my will. I didn't want to kill humans unlike him. I escaped my fathers grasp, hiding in mt. Ebott with my brother and sneaking out to get food. What he had done to me made my brother vengeful but he was scared, he didn't want to hurt humans either but the war changed him he started to get more aggressive along with me and all of monsterkind. Long story short, the prince was killed which caused a war, monsters won but humans trapped us underground and whenever a human falls... It's a death trap." He shrugged after summarising his story.  
"How come you didn't kill me?" He shrugged again and looked aimlessly around the room.  
"Welp, as your a good listener I'll tell you. I almost did. When I saw you hiding I knew you were a human and that you weren't a child but as I approached I felt something. A strange magical energy. It felt... weird like hopeful but dark." Void magic. "It did feel a bit like my fathers after he almost fell into the void. I wondered if you had ever came across him. I then noticed the scent. It was the smell of me before I went into hiding, the Sans that I used to be. I also noticed the hoodie that you were wearing, once it was the one that I wore. I couldn't kill you due to nostalgia but I couldn't leave you to be killed out there. So that's when I took you in." Sweet story really, you thought but something hit your mind what about Flowey?  
"Uhh... I know it's a weird question but do you normally talk to yourself? You sounded like you were talking to someone when you were hiding back then?" You opened your mouth to reply but in your relief the door was almost thrown off it's hinges and Papyrus marched in picking you up off the sofa and hugging you. You were so shocked that he did that, that you swore in alarm.  
"H-Holy shit, Papyrus!" He ignored your words and spoke in a worried tone.  
"We were so worried! Oh my god! I'm so sorry! He just came into our house and took you! I tried to stop him, I swear!" He voice much like Papyrus in your world but rushed in shock. You hugged him back in attempts to calm him.  
"I'm here for now. Don't worry I'm okay." Sans looked up at you in shock.  
"For now?" You nodded much to Sans and Papyrus's shock.  
"I have to go back, if I don't I'm not sure what he might do to me." Sans shook his head in disbelief.  
"You can't go back... No, not yet!" He exclaimed an idea came into your head.  
"Maybe I could stay the night? I could phone him to let him know that I would come back tomorrow?" Sans looked around thoughtfully for a moment then hesitantly nodded.  
You took out the phone that Gaster had given you out of your pocket and dialled his number to let him know that you wouldn't be back tonight.

You were determined to stay.

**Notes for the Chapter:**

> I was going to say something but I forgot... Uhhh.... nope, cant remember! xD  
> (Edit: I remember now! The 'backstory' that I wrote isn't true? I mean, I made it up because that's what I thought best matched, as far as I'm aware, I don't think there is an official backstory, so I tried my best to make one up! This goes for the other aus as well, the characters might not be 100% the same or the plotline but I'm trying to make it all work as good as I can get it! Thanks!)  
> Thank you NightWatchFreak and all of those guests for the Kudos! I should have thanked you earlier, sorry! However it's been so heptic lately that I haven't even realised there was so many kudos! Oh my god! Thank you so much for the support guys!  
> Oh and keep looking out for books! The next one is quite SWEET really! xD


	10. Drifting away

**Summary for the Chapter:**

> Final chapter of this world, no spoilers.

After a long conversation, Gaster had allowed you to stay but you had to be back at the lab tomorrow early.  
"So what did he say?" Sans asked. Papyrus had busied himself with making food in the kitchen.  
"Well I can stay but you're not gonna like this next bit. He's got a new set of experiment set up, he won't tell me what it is apparently it's a 'surprise'. I'm not liking the sound of it." His face dropped into shock.  
"No no no no no. You can't go back..." He spoke in shocked concern.   
"I have no choice, he says that he's gonna come and get me if I don't come back. His excuse being that he wants to make sure I'm safe." Sans shook his head in despair.  
"Clever bastard." You suddenly felt like you were being watched by an evil presence and looked around the room nervously. There wasn't anyone there. Or was there? You pushed your thoughts away and responded to Papyrus's calls of spaghetti by sitting down at the kitchen table.  
You all ate in companionable silence, eventually finishing. You helped Papyrus clean up, then sat down with Sans, watching tv together. Papyrus went to bed earlier after making a box of spaghetti for you to eat tomorrow. You thanked him as he climbed upstairs. Sans sat with you right into the early hours of the next day no matter how hard you tried you couldn't sleep thanks to the phone call about the new experiments Gaster had planned. Sans however, as you looked across at him, was asleep with his chin in his hand. You smiled and turned off the tv, settling back onto the couch and throwing a blanket over the two of you. You stared at the black screen thinking about what would happen to you tomorrow when the screen changed slowly from black to white. You started to hyperventilate waking up Sans. He looked at you in concern trying to calm you but your body didn't listen the room was whitening, the walls glitching and your soul was glowing a bright red to illuminate the room.  
"S-Sans! It's happening again!" He looked at you in concern grabbing your arm in panic.  
"I-I can't stop myself from teleporting away, I might even teleport to a place with no mercy." He shook his head he was the only thing you could see that wasn't white or glitching.  
"N-No! You can't go!" You nodded and he gripped you harder.  
"L-Look after Papyrus while I'm gone... I'll come back." He shook his head not wanting you to leave. His body started to glitch in front of you and your soul burned a eye blindingly, bright red and you vanished into thin air as he jumped forwards to stop you.

**Author's Note:**

> Thanks for reading!- Stay DETERMINED!


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